Mixed Spacer Multispectral Filter Oxidation Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multispectral filters used in sensor devices face challenges with environmental degradation and manufacturing difficulties due to the oxidation of hydrogenated silicon layers, leading to refractive index changes and center wavelength shifts, which affect the filter's performance and manufacturability.
Innovation Solution
A multispectral filter design incorporating a spacer layer structure with alternating layers of hydrogenated silicon and oxide materials, such as niobium titanium oxide or silicon dioxide, to maintain a controlled composition and refractive index, reducing oxidation and manufacturing difficulties, and enabling a higher channel count with improved durability and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hydrogenated silicon layers are used in the spacer structure, then high refractive index is achieved, but oxidation occurs leading to refractive index changes and center wavelength shifts
Solution Approach 1:
The patent employs a composite spacer structure combining hydrogenated silicon layers with oxide material layers. The hydrogenated silicon provides high refractive index (greater than 3.5) for effective spectral filtering, while the oxide layers (such as silicon dioxide, aluminum oxide, or titanium dioxide) provide environmental stability and oxidation resistance. This composite approach allows the filter to maintain its optical performance and center wavelength stability in various environmental conditions.
2Manufacturing precision
If thin layers are used to achieve fine channel spacing, then manufacturing precision is improved, but layers become susceptible to oxidation and degradation
Solution Approach 1:
The patent combines thin hydrogenated silicon layers (for precise optical control and channel spacing) with protective oxide layers. The oxide layers serve as both structural components and protective barriers, preventing oxidation of the thin hydrogenated silicon layers while maintaining the desired thin-layer configuration for fine channel spacing control.
Solution Approach 2:
The oxide material layers create an inert protective environment for the hydrogenated silicon layers, shielding them from oxidative degradation. This protective barrier allows the thin hydrogenated silicon layers to maintain their optical properties without undergoing oxidation-induced refractive index changes.
3Manufacturing precision
If alternating layers of high and low refractive index materials are used, then channel separation is improved, but device complexity increases
Solution Approach 1:
The patent uses a systematic composite structure with alternating hydrogenated silicon and oxide layers. Each layer's thickness is precisely controlled based on its refractive index to achieve the desired channel separation. The regular alternating pattern, while structurally complex, follows a predictable design methodology that facilitates manufacturing control and quality assurance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a durable and environmentally stable multispectral filter with reduced center wavelength shift and increased manufacturability, achieving high transmissivity and even channel spacing across the desired spectral range, enhancing the optical performance and reliability of sensor devices.
Implementation Method 1
Each layer, of the first set of layers, is a first material associated with a first refractive index and a thickness that is greater than a layer thickness threshold. The spacer layer structure includes a second set of layers. Each layer, of the second set of layers, is a second material associated with a second refractive index lower than the first refractive index.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An optical filter may include a first mirror, a second mirror, and a spacer layer structure disposed between the first mirror and the second mirror. The spacer layer structure may include a first set of layers. Each layer, of the first set of layers, may be a first material associated with a first refractive index and a thickness that is greater than a layer thickness threshold. The spacer layer structure may include a second set of layers. Each layer, of the second set of layers, may be a second material associated with a second refractive index. Each layer, of the second set of, may be selected to replace a corresponding layer of the first material. The corresponding layer may be associated with a thickness that is less than the layer thickness threshold.